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Left Dorsolateral Prefrontal Cortex (leave + dorsolateral_prefrontal_cortex)
Selected AbstractsRepeated high-frequency transcranial magnetic stimulation over the dorsolateral prefrontal cortex reduces cigarette craving and consumptionADDICTION, Issue 4 2009Revital Amiaz ABSTRACT Aims To evaluate the effect of repeated high-frequency transcranial magnetic stimulation (rTMS) of the left dorsolateral prefrontal cortex (DLPFC), combined with either smoking or neutral cues, on cigarette consumption, dependence and craving. Design Participants were divided randomly to real and sham stimulation groups. Each group was subdivided randomly into two subgroups presented with either smoking-related or neutral pictures just before the daily TMS intervention. Ten daily rTMS sessions were applied every week-day and then a maintenance phase was conducted in which rTMS sessions were less frequent. Setting Single-site, out-patient, randomized, double-blind, sham-controlled. Participants Forty-eight chronic smokers who smoked at least 20 cigarettes per day and were motivated to quit smoking. Healthy males and females were recruited from the general population using advertisements in newspapers and on internet websites. Intervention Ten daily rTMS sessions were administered using a standard figure-8 coil over the DLPFC. Stimulation included 20 trains/day at 100% of motor threshold. Each train consisted of 50 pulses at 10 Hz with an inter-train interval of 15 seconds. Measurements Cigarette consumption was evaluated objectively by measuring cotinine levels in urine samples and subjectively by participants' self-reports. Dependence and craving were evaluated by standard questionnaires. Findings Ten daily rTMS sessions over the DLPFC reduced cigarette consumption and nicotine dependence. Furthermore, treatment blocked the craving induced by daily presentation of smoking-related pictures. However, these effects tended to dissipate over time. Conclusions Multiple high-frequency rTMS of the DLPFC can attenuate nicotine craving. [source] Altered Impulse Control in Alcohol Dependence: Neural Measures of Stop Signal PerformanceALCOHOLISM, Issue 4 2009Chiang-shan Ray Li Background:, Altered impulse control has been implicated in the shaping of habitual alcohol use and eventual alcohol dependence. We sought to identify the neural correlates of altered impulse control in 24 abstinent patients with alcohol dependence (PAD), as compared to 24 demographics matched healthy control subjects (HC). In particular, we examined the processes of risk taking and cognitive control as the neural endophenotypes of alcohol dependence. Methods:, To this end, functional magnetic resonance imaging (fMRI) was conducted during a stop signal task (SST), in which a procedure was used to elicit errors in the participants. The paradigm allowed trial-by-trial evaluation of response inhibition, error processing, and post-error behavioral adjustment. Furthermore, by imposing on the subjects to be both fast and accurate, the SST also introduced a distinct element of risk, which participants may or may not avert during the task. Brain imaging data were analyzed with Statistical Parametric Mapping in covariance analyses accounting for group disparity in general performance. Results:, The results showed that, compared to HC, PAD demonstrated longer go trial reaction time (RT) and higher stop success rate (SS%). HC and PAD were indistinguishable in stop signal reaction time (SSRT) and post-error slowing (PES). In a covariance analysis accounting for go trial RT and SS%, HC showed greater activity in the left dorsolateral prefrontal cortex than PAD, when subjects with short and long SSRT were contrasted. By comparing PAD and HC directly during stop errors (SE), as contrasted with SS, we observed greater activity in PAD in bilateral visual and frontal cortices. Compared to HC, PAD showed less activation of the right dorsolateral prefrontal cortex during PES, an index of post-error behavioral adjustment. Furthermore, PAD who showed higher alcohol urge at the time of the fMRI were particularly impaired in dorsolateral prefrontal activation, as compared to those with lower alcohol urge. Finally, compared to HC subjects, PAD showed less activity in cortical and subcortical structures including putamen, insula, and amygdala during risk-taking decisions in the SST. Conclusion:, These preliminary results provided evidence for altered neural processing during impulse control in PAD. These findings may provide a useful neural signature in the evaluation of treatment outcomes and development of novel pharmacotherapy for alcohol dependence. [source] Transcranial magnetic stimulation for the deficit syndrome of schizophrenia: A pilot investigationPSYCHIATRY AND CLINICAL NEUROSCIENCES, Issue 3 2005PERMINDER SACHDEV md, franzcp Abstract, In an open study, four subjects with a stable deficit syndrome of schizophrenia received high frequency repetitive transcranial magnetic stimulation (15 Hz at 90% of motor threshold, 1800 pulses each session, daily for 20 sessions over 4 weeks) over the left dorsolateral prefrontal cortex. Subjects showed a significant reduction in negative symptoms and improvement in function, with no change in positive symptoms. This improvement was maintained at the 1 month follow up. Repetitive transcranial magnetic stimulation as a treatment of the deficit syndrome of schizophrenia is feasible, safe and may be beneficial. A systematic study in randomized control trials would be appropriate. [source] Brain,computer interfacing based on cognitive controlANNALS OF NEUROLOGY, Issue 6 2010Mariska J. Vansteensel PhD Objective Brain,computer interfaces (BCIs) translate deliberate intentions and associated changes in brain activity into action, thereby offering patients with severe paralysis an alternative means of communication with and control over their environment. Such systems are not available yet, partly due to the high performance standard that is required. A major challenge in the development of implantable BCIs is to identify cortical regions and related functions that an individual can reliably and consciously manipulate. Research predominantly focuses on the sensorimotor cortex, which can be activated by imagining motor actions. However, because this region may not provide an optimal solution to all patients, other neuronal networks need to be examined. Therefore, we investigated whether the cognitive control network can be used for BCI purposes. We also determined the feasibility of using functional magnetic resonance imaging (fMRI) for noninvasive localization of the cognitive control network. Methods Three patients with intractable epilepsy, who were temporarily implanted with subdural grid electrodes for diagnostic purposes, attempted to gain BCI control using the electrocorticographic (ECoG) signal of the left dorsolateral prefrontal cortex (DLPFC). Results All subjects quickly gained accurate BCI control by modulation of gamma-power of the left DLPFC. Prelocalization of the relevant region was performed with fMRI and was confirmed using the ECoG signals obtained during mental calculation localizer tasks. Interpretation The results indicate that the cognitive control network is a suitable source of signals for BCI applications. They also demonstrate the feasibility of translating understanding about cognitive networks derived from functional neuroimaging into clinical applications. ANN NEUROL 2010 [source] Corrected values of brain metabolites for the article: ,Abnormal cellular energy and phospholipid metabolism in the left dorsolateral prefrontal cortex of medication-free individuals with bipolar disorder: an in vivo1H MRS study'BIPOLAR DISORDERS, Issue 7 2008Benicio N. Frey No abstract is available for this article. [source] | ||||||||||